constant FPS drops in v1.16.1

FPS drops consistently for a few frames every several seconds in a new v1.16.1 world.  No mods or resource packs, render depth set to 8 chunks.  Happens whether exploring new chunks or building in a small area.  More noticeable when turning the camera.  FPS rating in F3 display drops to about half for a moment every time it happens.

Win7Pro / AMD A8-5600K APU / Radeon RX 560 series video